The present invention generally relates to servomechanisms. More specifically, the present invention relates to a self-powered and self-contained servomechanism for towing recreational vehicles, trailers, barges and the like.
A leading vehicle and a trailing vehicle interconnected in a manner permitting relative rotational movement while preventing relative linear displacement, such as the commonly-known tractor and trailer combination, operate as a single articulated vehicle. Each element of the combination is responsive to the forces and movements of the connected element as transferred through the articulative connection. A commonly-known disadvantage of such articulative connections is the problem of jackknifing, i.e. the failure of the leading vehicle to constrain the trailing vehicle.
Various attempts have been made within the art to effect control of one element of an articulated vehicle by another element of the combination. In U.S. Pat. No. 4,771,838 to the present Applicant a self-powered and self-controlling trailing vehicle is disclosed that operates in the absence of a power transmitting and control umbilical between a leading vehicle and the trailing vehicle. Thereby the responsiveness of the leading vehicle and the trailing vehicle are isolated from each other. The present invention discloses particular advantages over the trailing vehicle of the referenced U.S. patent including a greater variety of applications, better steering control of the trailing vehicle, and utilization of less power for control of the trailing vehicle.
In the trailing vehicle disclosed in the '838 patent, ground-engaging wheels are shown disposed at the rear of the trailing vehicle body. Thus, the trailing vehicle is susceptible to lateral movement at its forward end that must be corrected by the control means of the trailing vehicle. Such lateral movements may be caused by crosswinds, road protuberances and the like. As a result, the control means is required to do additional work beyond that required by active steering of the leading vehicle. Thus the control means is generally active even during straight line travel of the trailing vehicle which necessitates additional power requirements in the control means and contributes to fatigue in the control means. Furthermore, a trailing vehicle of the type disclosed in the '838 reference having the ground-engaging wheels disposed at the rear of the trailing vehicle is more difficult to steer since the point of rotation of the trailing vehicle is further displaced from the leading vehicle. And since the power and control means of the referenced trailing vehicle are constructed as an integral part of the trailing vehicle, applications of the invention of the '838 reference for towing is correspondingly limited to the particular trailing vehicle configuration, i.e., for example, a recreational vehicle so constructed cannot be used for towing machinery, equipment and the like generally carried on a flatbed trailer.